Bowers is believed to live in the Versailles borough of Pittsburgh, and has been described as a heavy set, white male with a beard, KDKA reported.

Since 1996, Bowers has legally bought at least six firearms, according to CNN, citing a law enforcement official.

He reportedly entered the synagogue shouting "All Jews must die," and had written anti-Semitic posts on social media. Pittsburgh authorities tweeted that the "shooting will be prosecuted as a Hate Crime and the FBI will be leading the investigation."

An hour before the shooting, Bowers wrote on a social media platform called Gab under the name One Dingo that "HIAS likes to bring invaders in that kill our people. I can't sit by and watch my people get slaughtered. Screw your optics. I'm going in," according to Heavy.com.